Contact device for electric master clocks



May 17, 1938. F. SCHNEIDER CONTACT DEVICE FOR ELECTRIC MASTER CLOCKSFiled Dec. 28, 1935 Patented May 17, 1938 UNITED STATES PATENT OFFICECONTACT DEVICE FOR ELECTRIC MASTER CLOCKS Ferdinand Schneider, Fulda,Germany Application December 28, 1935, Serial No. 56,457

3 Claims.

This invention relates to contact-devices for electric master-clockswhich serve for operating secondary electric clocks. In heretofore knowncontact-devices used for this purpose currentcarrying contact-springshave been used, said contact-springs carrying the operating current forthe secondary clocks. These known contactdevices have the disadvantagethat they do not permit passage of a relatively strong operating currentso that only a small number of secondary clocks can be operated from themaster-clock. Furthermore, known contact-devices are liable to relaxafter some time, that is the contact-members will lose their tension,and in consequence thereof the contact-pressure will soon be diminishedwith the result that a safe and reliable making-of the contacts cannotbe attained with certainty for a greater length of time.

According to this invention, the aforementioned current-carryingcontact-springs are replaced by contact-levers which are amplydimensioned in cross-section, said contact-levers cooperating withcontact-pins alternately brought into eflicient sliding contacttherewith. In order to attain a reliable and intimate contact, the freecontact-levers are pivotally mounted atone of their ends, while theother of their ends are connected with each other by means of atensionspring keeping together both contact-levers.

Moreover, all of said contact-levers are properly supported in such amanner that one contactlever is being firmly pressed against itscompanion contact-member, in the present case a contact-bar, wheneverand as long as the other contact-lever is in sliding contact with itscompanion contact-member, that is in'the present case a contact-pin on acontact-disk. In consequence of this improvement in the making of thecontact, the contact-resistances will practically be reduced to nil, sothat the electric circuit associatedwith the contact will be able tooperate a greater number of secondary clocks than had heretofore beenpossible. In addition to the aforementioned contact-levers which servefor the making of the main contacts, there are further provided twoauxiliary contact-levers in parallel to the former, said auxiliarylevers serving to suppress the formation of sparks at the main contacts.These auxiliary contact-levers are likewise operated by a commontension-spring under most reliable conditions with respect to making thecontacts for the spark-extinguishing circuit.

As the main and auxiliary contact-levers never change their contactposition, these contactorgans will warrant a permanently reliableoperation of secondary clocks from a master-clock.

In the accompanying drawing I have represented two examples ofconstruction of my novel contact-device for electric master-clocks, Fig.'1 being a front-view of a contact-device including 5 main contacts,spark-extinguishing contacts, and the electric circuits operated by saidcontacts, Fig. 2 a section along line AB of Fig. 1, Fig. 3 a front-viewof my novel contact-device without a spark-extinguishing circuit, thedevice being shown in condition of rest, and Fig. 4 the contactdeviceshown in Fig. 3 in condition of making contact.

In the construction of the contact-device shown in Figs. 1 and 2, theclockwork of the master-clock is provided with an arbor 4 rotated at aconstant speed by the clockwork and has an insulating plate 2 mounted onplate I by means of screws 3. On an extension of the arbor 4 passingthrough the plate I, there is mounted an insulating tube 5 carrying thecontact-disk 6. On so the latter is mounted a contact-pin I and oneither side thereof an insulated pin 8 and 9. To the plate I of theclockwork there is further fastened an insulating bushing ill, acontact-bolt ll being mounted in said bushing. The bolt H forms thecarrier of a sliding-spring l2, the free end of said spring sliding onthe periphery of a contact-disk 6 in full contact therewith. Theinsulating plate 2 further carries the bindingposts or terminals l3, l4,l5, l6 and H, the contact-levers 22, 23, 24 and 25 being pivotallymounted on said binding-posts or terminals by means of set screws I8,l9, 2| and 20, respectively. The terminal l5 extends in upward directioninto a current-bar 26, which carries at its upper end a contact-memberpreferably in the form of a silver-plate 21. The contact-levers 22, 23,24 and 25 are re-inforced at their inner surfaces by means ofsilver-straps 22a, 23a, 24a and 25a and more particularly at thosesurfaces at which they come in contact with the contact-pin 1 servingfor establishing the electric circuit for the operation of the secondaryclocks. The auxiliary contact-levers 22 and 25 are arranged in front ofsaid main contact-levers 23 and 24 at some distance therefrom andparallel thereto.- Swinging motion of said auxiliary contact-levers islimited ininward direction by fixed stops 28 y and 29 on the insulatingplate 2. At the height of the contactedisk 6 the inner distance betweensaid two auxiliary contact-levers 22 and 25 is somewhat smaller thanthat between the main contact-levers 23 and 24. From the contact-bolt llleads a connection 30 to the negative pole of 38. The lead 3A isconnected by the lead 39 with the one terminal of a secondcoherer-resistance 40, the other terminal of the latter being connectedto the terminal ill by the lead 4i. At the head-end of the maincontact-levers 233 and 2d are provided insulating rollers 42 and 43 towhich a tension-spring 44 is fastened, said tensionspring keepingtogether said two main contactlevers atthis place. In like manner,insulating rollers it and it are provided at the head ends of saidauxiliary contact-levers and 2%, said insulating rollers serving asanchorages for the ends of the tension-spring ii.

Th construction shown in Figs. Z-iand 4 from that shown in Figs. 1 and 2solely therein that the auxiliary contact-levers as well as thecoherer-resistances ill and dd, which are used as additional organs forspark-extinguishing, are omitted.

The operation of the abovedescribed device is described in thefollowing, the main contacts according to Figs. 3 and 4 being describedin inoperative condition. All parts of the contactdevice are in theposition shown in Fig. 3. Upon rotation of the contact-disk 6 indirection of the arrow, first the insulating pin ii on said disk willabut against the contact-lever23 and press the latter away from itsposition of rest on the contact-member 2i. Upon continued rotation ofsaid disk 6 the contact-pin i thereon will come in conductive connection.with the contact-lever 23 as shown in Fig. 4, thereby establishing anelectric circuit 3i, 3!], ll, i2, 3, l, 23, i4, 35, 34, I6, 24, 2i, 26,i5, 32, the secondary clocks being now moved forward one minute. Thismaking of the contact according to this invention takes place withoutresistance which is due, on the one hand, to the greater tension of thespring 44 firmly pressing the contact-lever 24 against the front surfaceof the contact-member 21, and on the other hand, to the sliding of-thecontactpin 1 in full contact along the contact-lever 23. Upon furthercontinued rotation of the contactdisk 6, now the insulating pin 9 abutsagainst the contact-lever 23, causing the contact-lever 23 to returninto its inoperative position onto the contact-member 21, somewhatsubsequently to the interruption of the contact between the pin 1 andthe contact-lever 23. Subsequent contact between the pin 1 and thecontact-lever 24 is effected in like manner to cause change of.direction of the current supplied to the secondary clocks. In order-tosuppress sparking at the contact, the contact-device is constructed asshown in Figs. 1 and. 2. In this construction of the contact-device thecoherer-resistance 31, is connected across the terminals of theauxiliary contact l3 and of the main contact ll by way of the leads 36and 38; while the 'coherer-resistance 40 is connected across theterminals of the auxiliary contact I1 and of the main contact I6 by wayof the leads and II. Prior to the position of operation, according toFig. 4 which shows a construction of the contact device' withoutsparkextinguishing means, the auxiliary contact-lever 22 which abutsagainst the pin 28 had been gripped by the contact-pin l and moved awayfrom'said pin 28. By this an electric circuit is at firstpreliminarilyestablished by way of the coherer-resistance 31 and after some time thecontact-pin i abuts against the main contactlever 23 to fully establishthe electric circuit. During the operation of contacting both.contact-levers 22 and 23 will be in contact with the pin 1. Upon furtherrotation of the contactdisk 6 the main contact-lever 23 will come out ofcontact with the pin l and first interrupt the circuit. The electriccircuit, however, still remains closed by way of the coherer-resistance3'! and somewhat later the circuit is fully interrupted, when thecontact-pin l comes out of contact with the auxiliary contact-lever 22.During the subsequent operation, the connection is made in like mannerby way of the other two contactlevers and .25 in cooperation with thecoher er-resistance 6U. Owing to the employment of contact-levers whichare operating resiliently one against the other, there will be secured aproper and uniform operating motion of the contact-device, with theresult that in the constructions shown in Figs. 1 and 2 sparking will beefficiently suppressed at the contacts and the latter remain free of theformation of oxide.

I claim:

1. A switch mechanism for electric mastercloclrs comprising, a diskhaving a conducting surface and rotated at constant speed, means toconnect the conducting surface of said disk to a source of current, apair of rigid contact arms pivotally mounted adjacent said disk, oneupon each side of the axis thereof, a pin secured to said disk inconducting relationship with the conducting surface thereof andengageable alternately with said contact arms, a tension spring havingits ends secured to but insulated from the free ends of said arms andoperable to swing said arms toward the axis of said disk, and a'fixedcontact element arranged alternately to make electrical contact withsaid contact arms and form a stop for limiting the swinging movement ofsaid arms toward the axis of said disk.

2. In a switch mechanism for master-clocks, the combination of a diskrotated at a constant speed, means to connect one terminal of a sourceof current to said disk, a fixed contact, means to connect said fixedcontact to the other terminal of the source, a pair of pivotally mountedrigid contact arms, a single spring for swinging said arms toward oneanother and into engagement with said fixed contact, and means on saiddisk alternately engageable with said arms to move said arms away fromsaid fixed contact against the tension of said spring and thereafter tomake an electrical contact with the arm.

3. In a switch mechanism for master-clocks of electrical clock systems,the combination of a fixed contact, a. pair of pivotally mounted rigidcontact arms, resilient means to force said arms into contact with saidfixed contact, and means operable alternately to move said arms fromcontact with said fixed contact, said means comprising insulating meansfor engaging said arms while they are in close proximity to said fixedcontact, and conducting means for completing electrical circuits throughsaid arms after the .latter have been moved from contact with saidfixedcontact.

FERDINAND SCHNEIDER.

